Pickups and drop tuning

[rbonner]

Gentlemen,

I have a modified 2007 American Deluxe Jazz that I recently converted to B-E-A-D by installing the four lower strings of a 5string set.

This bass has the SCN pickups and the factory EQ preamp.

I have noticed the output on the B string is less than the E string. I have already tilted up the pickups on the B string side, now makes a nice place to rest my thumb on occassions.

The pickups have the poles that stick up to different heights under the strings and I believe these are for adjusting the volume of each string. Just like my old Humbucker on the EB-0.

First are these actually adjustable or set by the factory? The last thing I want to do after modifying the crap out of my bass is to bust the pickups clamped in a vice banging on them with a sledgehammer.

If they are adjustable I'd like to lower the poles under what is now the E string and raise the ones under the B.

Also is there a "better" pickup for a drop conversion like this?

I will be making the obvious mods to the amplifier and cabs, so lets not bring up those issues, I'm only interested in Bass mods with this thread.

Plus these buggers are real AC hum pickeruppers and in my practice space I'm constantly NULLING out hum from adjacent wiring.

Anyway Thanks,

BOB

[SpamBot]

Either they will be adjustable from the top with a screwdriver or not at all.
DiMarzio's super J's or whatever they're called has adjustable pole peices, are cheap AND sound bitchin. Give them a look-see if you decide to change pups.

[SGD Lutherie]

What brand strings are they? Some low B's are really bad (like GHS).

My low B is as loud if not louder than the E.

The SCN pickups are supposed to be hum canceling (stacked humbcukers). You shouldn't be getting any hum.

You cannot change the hight of the poles on those pickups, but you can change the hight of the pickup it self, and each end can be adjusted as needed.

Also did you re-slot the nut to fit the heavier strings?

[rbonner]

HI David,

These strings are Chromes.

The hum I'm getting is induced by the main power feed coming into my house. It runs right under the floor in my practice space. If I turn exactly 90 degrees to the power wiring it nulls completely. if I'm across the room from the wiring I need to turn parallel to the feed.

The pickups are acting just like they are supposed too... But its irritating to have to position perfectly to null the hum.

I have already raised the B side of the pickups as far as they will go. I'd just like to see a little more zoom off the B. I am now pretty limited volume wise by the 810 cabinets, so I will be adding some subs to boost the sub 40HZ performance.

As far as the nut, the action is grand. I had the local Luthier jewell the frets. They are as level as a pancake and micro polished. They just shine.

When I did the nut, the first three frets are like just pushing down on next to nothing. Its just beautiful. I spent a lot of time with it.

Thats why I'd like to see if there's additional cool stuff I could do. Guys like Billy Sheehan do a Gibson humbucker under the neck and run it to separate amplifers, and stuff like that.

I dont think I'm ready to go that far yet, but I was curious if there are pickups that help the B string conversion some.

BOB

[SGD Lutherie]

I've never used the 5 string set of Chromes, but back when I used flats a lot I didn't care for them. The D string sounded unbalanced.

I did recently put some TI Jazz flats on my 5 string, and that low B was very nice.

Some noise sources are hard to kill with humbuckers. Like sitting in front of a CRT monitor or light dimmers. That's where better shielding comes in.

I have no experience with those pickups, but I would expect them to be quieter than that.

[rbonner]

Yeah I am probably just imagining it. BOB

[GlennW]

Would putting a little teeny tiny neo disc on the bottoms of the B poles be a bad idea? It might increase the output of that string.

[SGD Lutherie]

Originally Posted by GlennW

Would putting a little teeny tiny neo disc on the bottoms of the B poles be a bad idea? It might increase the output of that string.

I'm not sure... those pickups are already using Samarium-cobalt magnets, and the bottom pole is the same polarity as the top pole... the magnets are between the two coils. Maybe one on the top of the pole... but I doubt it will get much louder.

If the low E wasn't weak before the string change, than it's the strings and not the pickup.

Maybe it's a bad string. I had a dead sounding E string not long ago. They are real good about that and will send you a couple in the mail for free. Just email them or call them up.

[NorCal Dog]

Originally Posted by SGD Lutherie

If the low E wasn't weak before the string change, than it's the strings and not the pickup.

Maybe it's a bad string.

+1 on the strings

i have a set of the SCN fivers & they're very balanced between the strings

i had a few BEAD basses in the past, 'till i found out i really missed my G.

bought a couple fivers, never looked back

[Ric5]

Originally Posted by NorCal Dog

i had a few BEAD basses in the past, 'till i found out i really missed my G.

bought a couple fivers, never looked back

+1

[SGD Lutherie]

Originally Posted by NorCal Dog

+1 on the strings

i have a set of the SCN fivers & they're very balanced between the strings

The SCNs were designed by Bill Lawrence... I can't imagine they would suck.

bought a couple fivers, never looked back

+1

I haven't played a four string in the past 15 years! Once you go five, the fours are just jive! (God, that was awful! )



(Unlike Jeff, I wont be making my two '74 Rics into fivers)

[GlennW]

Originally Posted by SGD Lutherie

I'm not sure... those pickups are already using Samarium-cobalt magnets, and the bottom pole is the same polarity as the top pole... the magnets are between the two coils.

Thanks for explaining that, I had no idea they were made that way.

[SGD Lutherie]

Originally Posted by GlennW

Thanks for explaining that, I had no idea they were made that way.

From the patent. 8a - 8c are the magnets. 7a & 7b are "moderator bars" also known as "keepers". This is the guitar version of course, but same idea for the Jazz.

[rbonner]

The balance issue is I think because the E is now sitting where the A string was previously, the poles under the A were jacked up about a 1/16th.

SO are those things GLUED in there? Nobody has really answered that. But hinted they are not adjustable.

I don't think I have a flat string new out of the bag, I think a lot of this is just a combination of a lot of NEW ISSUES that need to be reconciled and my lack of experience with anything below an "E".

The D string is a little GAY too but the 4th position the poles are the lowest. It is a bit louder than it was when in the third position.

Maybe going to some pickups with adjustable poles might be an answer? Dimarzio J's?

I might be overly picky too. I just want to crank the B a bit more. OK so from all my research it doesn't look like there's anything special in the design between a 5 string pickup and a 4 string pickup as far as the B spot in the things.

There's also the fact that my 810 cabs are probably 20DB down at 30Hz compared to at 40Hz... I really won't know for sure what I'm hearing until I get amplification and drivers rated for the Bottom end.

This is a new realm for me. But I will be adding some big stuff and can balance a lot on just that string.

I thought about just going 5 string, but I really didnt care to much for the G string anyway. Sure when it was there, I used it, HAHAHA. But I can find the equivellent notes on those other 15 frets on the D string.

We might be able to play a lot of the stuff we'll be doing in a different Key also to utilize the B more. Thats what I will probably do.

Any new matterial will utilize the low notes. I'm having a lot of fun with this.

I appreciate the help and the tech talk. I've never really dug into pickups and bass electronics, always stuck with whatever "Mr Manufacturer" bolted on. But now-a-days there's a lot of aftermarket stuff for the jazz.

Oh one more thing, then there's nothing in the EQ on the bass then either that is different from the active electronics on the JAZZ V that could be limiting the B output?

Thanks Guys,

BOB

[SGD Lutherie]

Originally Posted by rbonner

The balance issue is I think because the E is now sitting where the A string was previously, the poles under the A were jacked up about a 1/16th.

Yeah, because the fingerboard is curved. The strings are higher in the middle, so the poles extend to reach them. The A wasn't louder than the E was it?

I think it's the string.

[rbonner]

No I don't think I remember it being louder.

Is there a way to measure this exactly? Basically take away the amplifier and speaker factor. I suppose if I had a scope I could measure the output and see what the voltage output is. Being an active bass we have that factory preamp/EQ in there too. BOB

[SGD Lutherie]

Try this, get another E and replace the B temporarily and see if they sound balanced. It doesn't matter that the B is tuned lower, and it's also a much larger string. It should be more balanced. If another E sounds the same than it's the string.

There's not really a way for one string to not be as loud on a pickup like this anyway. There is one coil under all the strings, and the magnets span several strings at a time. So even though you have separate pole pieces, it's the same magnet under the B and E.

Also try raising the B higher at the bridge. It might be fretting out on the fingerboard.

[rbonner]

It's not hitting the fingerboard, I've got the action puuuurfect. I played fretless for 15 years and I like them low, but I have zero fret buzz.

I do have a couple 105 E strings from my other sets... This is a 100 with the 5 string set I could string that back up. Don't have spare B's would have to buy one.

What I dont know is when the tech did the Fret Jewell and installed the BA II on the thing, I dont know if he repositioned the neck to make up for the bridge's higher height.

I actually pulled out the Fender manual for my bass and in a few minutes I'm going to check the actual pickup to string height spec and see if they are off at all. They might be a little wide.

David, thanks for the extra info, I studied the pic you posted and looked into how pickups were actually made. Never messed with them at all in 40 years, but starting to expand the horizons some with this stuff.

BOB

[GlennW]

Originally Posted by SGD Lutherie

From the patent. 8a - 8c are the magnets. 7a & 7b are "moderator bars" also known as "keepers". This is the guitar version of course, but same idea for the Jazz.

Thanks again. It's sort of like a Gibson EB-0 HB without the sidewinder layout, I think. Interesting stuff.

[SGD Lutherie]

Originally Posted by GlennW

Thanks again. It's sort of like a Gibson EB-0 HB without the sidewinder layout, I think. Interesting stuff.

Think of it like a P-90 with another coil on the bottom under the magnets, and the screws running though both coils.

Bill probably found that using two long SC magnets was too strong. He talks about not wanting to saturate the core in the patent. So he has the "moderator" bars between the magnets and the poles.

But it is like the Fire/Thunderbird sidewider turned 90 degrees. Of course Bill designed those as well.